B. hominis is reclassified from the yeasts to the parasitic protozoa of man. A toxin from this organism causes inflammation, necrosis, hemorrhage and fluid collection in the isolated ileal segment of the rabbit. Nine blood cultures can now be monitored on our impedance signaling instrument through a programmed sequence in the Tektronix B1 computer. Conversion to the IBM PDP 11 computer will enlarge this capacity to handle 50 cultures which should be sufficient for present and future needs. The lysis-membrane filtration blood culture technique developed is yielding more positive blood cultures than the conventional blood culture system. The lysing solution developed here is non-toxic to all of the pathogenic bacteria tested and antibiotics present in patients blood are removed. Also, bacteria present are concentrated for culture. Analysis of the phage typing data to date reveals: 1. That the "major" epidemic strains of S. aureus increased in the early 1960's to high levels and declined in the mid-1960's, not to reappear. 2. The world-wide epidemic strain 80/81 appeared in the Clinical Center in March of 1959, immediately spreading through the hospital and via employees, to their families. It disappeared from the Clinical Center in 1965, and has not reappeared. 3. At present there are in the Clinical Center no "epidemic types." 4. Phage typing patterns are less clearcut, particularly in the mixing of reactions of phage and from lytic groups I, II, III, and Miscellaneous.